Tunable intersubband Raman laser in GaAs/AlGaAs multiple quantum wells

A new tunable source of infrared radiation based on intersubband electron Raman scattering in semiconductor quantum wells is studied theoretically. The structure consisting of three levels in two coupled GaAs/AlGaAs quantum wells is optimized for a maximum Raman gain at zero bias. Raman gain as large as $400/\mathrm{cm}$ can be achieved according to our calculations. Lasing wavelengths are tuned when an external dc bias field is applied along the growth direction. An infrared tuning range of 8–12 μm with moderate Raman gain is predicted as the electric field is varied from $-40$ to 40 kV/cm.